Pressure relief cushion

ABSTRACT

PRESSURE RELIEF CUSHION, SUCH AS A CORN RING, COMPRISING A BODY OF A FLEXIBLE FOAM MATERIAL HAVING A CENTRAL APERTURE THEREIN, THE WALL OF THE BODY WHICH DEFINES THE APERTURE HAVING A GROOVE EXTENDING RADIALLY OUTWARDLY FROM THE WALL TOWARD THE PERIPHERY OF THE BODY.

United States Patent O 3,606,886 PRESSURE RELIEF CUSHION Ernst Bittner, Frankfurt am Main, Germany, assignor to The Scholl Mfg. Co., Inc., Chicago, Ill. Filed Dec. 29, 1969, Ser. No. 888,573 Claims priority, application Germany, Aug. 29, 1969, P 19 43 892.7 Int. Cl. A61f 5/30 U.S. Cl. 128-153 7 Claims ABSTRACT OF THE DISCLOSURE Pressure relief cushion, such as a corn ring, comprising a body of a flexible foam material having a central aperture therein, the wall of the body which defines the aperture having a groove extending radially outwardly from the wall toward the periphery of the body.

BACKGROUND OF THE INVENTION Field of the invention This invention is in the field of pressure relief cushions which are exemplified by corn rings which are adhesively applied about the affected area to prevent pressure on the sensitive area by shoe uppers. The improvement of the present invention is involved in a particular configuration of the corn ring whereby through the provision of a groove intermediate the upper surface and bottom surface of the ring, so that a greater amount of deflection can be absorbed by the ring without transmitting pressure to the affected area of the skin.

DESCRIPTION OF THE PRIOR ART There are typical corn rings or pads presently being marketed that are ring-shaped or oval shaped. These corn pads are die cut from a sheet of suitable material such thatthe resulting pad is generally cylindrical in configuration having a rectangular cross-section in an axial plane. This type of pad is not particularly satisfactory because the shoe presses upon a sensitive area of the foot over this relatively thick pad. To reduce the disadvantages of this type of structure, it has been suggested that the inner part of the pad be compressed so that the thickness of the wall defining the central aperture of the pad is reduced. Such corn pads usually are provided with a pressure sensitive adhesive bottom surface, so that a relatively firm zone of material exists around the central aperture. Thus, despite the reduced thickness of the pad, the desired relief is not always obtained.

SUMMARY OF THE INVENTION The pressure relief cushion of the present invention includes a body of flexible foam which is either oval or ring shaped and which is provided with the usual centrally disposed aperture to fit over the affected area of the toe. The cushion is profiled, however, so that it can absorb a substantial amount of compression from a shoe upper without transmitting pressure to the sensitive area of the toe. To this end, the wall of the foam body which defines the central aperture has a groove formed therein of V-shapcd configuration in cross-section by providing a void into which an upper portion of the pad can be compressed without transmitting the pressure to the sensitive area of the toe. The configuration of the cushion also includes a rounded contour on the inner wall of the pad which extends upwardly from the groove to the upper surface of the pad body. The relief cushion also has, in the preferred embodiment, a convex contour extending from its upper surface to its outer periphery.

3,606,886 Patented Sept. 21, 1971 Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

FIG. 1 is a plan view, on a greatly enlarged scale, of a corn pad embodying the improvements of the present invention; and

FIG. 2 is a cross-sectional view taken substantially along the line IIII of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, reference numeral 10 indicates generally a corn pad produced according to the present invention, the pad consisting of a foam body 11 having a central aperture 12, and having its bottom surface covered with a pressure sensitive adhesive layer 13. The foam body 11 may be composed of material such as a foamed polyurethane resin, a foamed polyvinyl chloride, foamed polyethylene, foamed polystyrene, a butadiene-styrene foam or foam rubber.

The interior wall surface of the foam body 11 which defines the aperture 12 is, in accordance with the present invention, provided with a groove 14 which typically extends from the bottom surface of the pad and is generally V-shaped in cross-section. For best results, the depth of the groove 14 identified at A of the drawing is less than one-third of the radial width B as illustrated in FIG. 2 of the drawing.

The inner wall of the pad 10 is also provided with a rounded contour 15 which extends from the upper end of the V-shaped groove 14 up to the top surface 16 of the corn pad. Additional advantages in cushioning effect are provided by utilizing a convex outer surface 17 extending from the upper surface 16 of the corn pad to the bottom surface 18 thereof.

In a companion application, Ser. No. 888,575 filed Dec. 29, 1969 there is described a method and apparatus for producing arcuately shaped, internally notched corn pads of the type as shown herein. As described in the co-pending application, such corn pads can be made in a continuous manner by providing a set of rigid molds on a conveyor belt, each of the molds having a molding cavity which includes an undercut portion. The molding cavity is partly filled with an expandible foam such as the foamable polyurethane composition and is then covered with a doubly coated strip, coated on both sides of the pressure sensitive adhesive. This adhesive strip serves to provide a closure for the molding cavity so that as the foamable composition expands, it is confined and molded into conformity with the molding cavity. At the same time, the molding of the polyurethane foam provides an integral, relatively non-porous skin on the molded product.

In the type of apparatus described in said aforementioned co-pending application, the individual mold peripheries are provided with a knife edge so that upon completion of the expansion of the foamable material into conformity with the molding cavity, the application of pressure against the knife edges causes the adhesive strip to be severed. The resulting laminated product consisting of the molded foam and the strip secured thereto is then lifted out of the mold by applying a web of an adhesive receptive material to the adhesive strip and exerting a pulling force on the web.

A typical foamable polyurethane composition, as described in theaforementioned co-pending application is the following:

Component A Parts by wt. Polypropylene ether triol (M.W. 1500) 15 Polyethylene glycol ether (M.W. 2000) 30 Dibutyl tin dilaurate 0.5 Triethylenediamine 0.8 Trichlorofiuoromethane 30 Silicone DC 190 0.8 Water 1.8

Component B Diphenylmethane diisocyanate 38.5

The two above-identified components can be mixed together briefly and then applied by means of the spray gun as illustrated in the drawings. The foaming, reaction and polymerization of the components to form a polyurethane ether foam takes about 3 to 5 minutes. The specific gravity of the foam is between 0.06 and 0.12 depending upon the ratio of ingredients.

It will thus be understood that the pressure relief cushion of the invention protects the sensitive area of the toe from pressure such that the cushion can be compressed from its original thickness without increasing the pressure that comes from the shoe upper.

I claim as my invention:

1. A pressure relief cushion comprising a body of flexible foam having a substantially flat undersurface, adhesive on such undersurface and a central aperture in such body, the wall of said body defining said central aperture having a groove extending radially outwardly from said wall toward the periphery of said body.

2. The relief cushion of claim 1 in which the groove is V-shaped in cross-section.

3. The relief cushion of claim 1 in which said groove extends less than one-third of the distance from said wall to said periphery;

4. The relief cushion of claim 1 in which said wall has a rounded contour extending upwardly from said groove to the upper surface of said body.

5. The relief cushion of claim 4 in which said body has a convex contour extending from its upper surface to its outer periphery.

6. The relief cushion of claim 1 in which said foam is a polyurethane foam.

7. The relief cushion of claim 6 in which said polyurethane foam has an integral, relatively non-porous skin.

References Cited UNITED STATES PATENTS 1,984,158 12/1934 Scholl 128-153 2,030,911 2/1936 Borden 4017X 2,227,588 1/ 1941 Kemp 15244CHX FOREIGN PATENTS 1,166,413 3/1964 Germany.

ROBERT W. MICHELL, Primary Examiner L. ANTEN, Assistant Examiner 

